This application claims the priority of German patent document 198 07 126.4, filed Feb. 20, 1999, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a method for controlling the drive performance of a motor vehicle having an internal combustion engine with spark ignition.
German patent document DE 44 07 475 A1 discloses such a method, in which the ignition angle, the air/fuel ratio and the load are influenced based on a setpoint for the torque to be delivered by the drive unit.
The goal of the present invention is to provide an improved method for adjusting the drive performance of a motor vehicle with an internal combustion engine with spark ignition, such that a centrally specified desired torque can be achieved simply and reliably for different dynamic requirements.
This and other objects and advantages are achieved by the control method according to the invention, in which three operating state are identified and output torque is controlled according to a different criterion for each. In a first operating state, the torque is adjusted with optimum efficiency by load regulation; in a second operating state the torque adjustment is made as rapidly as possible by an additional ignition angle adjustment. Finally, in the third operating state the torque specification for load regulation is established and the remaining torque adjustment is made by an additional ignition angle adjustment.
In engine control, the coordination of the various demands on the vehicle drive is decoupled by the method according to the invention from the functions that adjust the internal combustion engine. The torque interface merely provides a desired torque and information on the dynamics with which this torque requirement is to be adapted to control the engine. It is immaterial in this regard how many partial systems are involved in the torque interface and how the current coordination is performed. By creating three operating states in which the requirements are met with different dynamics and with different goals, the various requirements of all the partial systems can still be taken into account.
By creating a transitional operating state with an associated threshold value for an ignition angle correction factor, it is possible to prevent abrupt retardation of a major ignition angle adjustment (and hence a perceptible change in torque), such as could result from a direct transition from an operating state with ignition angle adjustment, to an operating state without ignition angle adjustment.